1. Field of the Invention
The present invention is directed generally to systems and methods for reducing or eliminating effects of interfering radio frequency signals on cable customer premises equipment devices and outside plant.
2. Description of the Related Art
It has been reported that cable customer premises equipment (“CPE”) devices, such as cable set-top-boxes, cable modems, and embedded multimedia terminal adapters (“EMTAs”), are experiencing problems functioning properly in the presence of wireless telephones because wireless telephones introduce interfering radio frequency (“RF”) signals into the CPE devices. While many CPE devices include shielding that helps reduce such interfering wireless signals inside the CPE devices, the amplitudes of some strong wireless signals (e.g., RF signals used by wireless Long Term Evolution (“LTE”) cellular telephones) are large enough to cause signal-processing problems in the CPE devices. Further, retail grade cable and RF splitters used by some people in their homes can be highly susceptible to RF interference. Thus, cable and RF splitters may receive interfering signals and function as a point of ingress into CPE devices for interfering signals.
Currently available methods of dealing with problems caused by interfering RF signals involve either abandoning the use of some frequencies (e.g., those experiencing significant RF interference) by a cable system, and/or increasing the shielding of the CPE devices. Abandoning the use of some frequencies is undesirable because doing so reduces data bandwidth and the number of video channels available to customers. Unfortunately, increasing the shielding of the CPE devices simply does not provide enough isolation from the interfering RF signal in some cases.
A similar problem occurs in the outside plant portion of a cable television distribution systems. In recent years, the Federal Communications Commission has been allocating larger and larger portions of frequency spectrum used by cable television distribution systems to wireless service providers. Thus, wireless transmissions originating from such wireless service providers may interfere with cable signals distributed by the outside plant. Additionally, interfering signals (e.g., signals broadcast on the same frequency or frequencies used by cable television distribution systems) originating from other transmitting devices (such as broadcast television stations) may introduce noise into cable signals. While the various components of the outside plant may include shielding, some interfering signals may nevertheless be received by the outside plant and may introduce noise into the cable signals distributed by the outside plant. In some cases, it is not practical to increase the shielding to eliminate the interference.
Therefore, a need exists for methods of reducing and/or eliminating interfering signals in the outside plant and/or CPE devices. Noise reduction devices and/or CPE devices configured to operate in the presence of strong wireless signals would be particulary desirable. The present application provides these and other advantages as will be apparent from the following detailed description and accompanying figures.